Quantitative evaluation of simulated human enamel caries kinetics using photothermal radiometry and modulated luminescence

2011 ◽  
Author(s):  
Adam Hellen ◽  
Andreas Mandelis ◽  
Yoav Finer ◽  
Bennett T. Amaechi
2017 ◽  
Vol 24 (5) ◽  
pp. 1056-1064 ◽  
Author(s):  
R. D. Free ◽  
K. DeRocher ◽  
S. R. Stock ◽  
D. Keane ◽  
K. Scott-Anne ◽  
...  

Dental caries is a ubiquitous infectious disease with a nearly 100% lifetime prevalence. Rodent caries models are widely used to investigate the etiology, progression and potential prevention or treatment of the disease. To explore the suitability of these models for deeper investigations of intact surface zones during enamel caries, the structures of early-stage carious lesions in rats were characterized and compared with previous reports on white spot enamel lesions in humans. Synchrotron X-ray microcomputed tomography non-destructively mapped demineralization in carious rat molar specimens across a range of caries severity, identifying 52 lesions across the 30 teeth imaged. Of these lesions, 13 were shown to have intact surface zones. Depth profiles of fractional mineral density were qualitatively similar to lesions in human teeth. However, the thickness of the surface zone in the rat model ranges from 10 to 58 µm, and is therefore significantly thinner than in human enamel. These results indicate that a fraction of lesions in rat caries possess an intact surface zone and are qualitatively similar to human lesions at the micrometer scale. This suggests that rat caries models may be a suitable analog through which to investigate the structure of surface zone enamel and its role during dental caries.


2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Frank Lippert

This study aimed to investigate the effect of enamel caries lesion baseline severity on fluoride dose-response under pH cycling conditions. Early caries lesions were created in human enamel specimens at four different severities (8, 16, 24, and 36 h). Lesions were allocated to treatment groups (0, 83, and 367 ppm fluoride as sodium fluoride) based on Vickers surface microhardness (VHN) and pH cycled for 5 d. The cycling model comprised 3 × 1 min fluoride treatments sandwiched between 2 × 60 min demineralization challenges with specimens stored in artificial saliva in between. VHN was measured again and changes versus lesion baseline were calculated (ΔVHN). Data were analyzed using two-way ANOVA (p<0.05). Increased demineralization times led to increased surface softening. The lesion severity×fluoride concentration interaction was significant (p<0.001). Fluoride dose-response was observed in all groups. Lesions initially demineralized for 16 and 8 h showed similar overall rehardening (ΔVHN) and more than 24 and 36 h lesions, which were similar. The 8 h lesions showed the greatest fluoride response differential (367 versus 0 ppm F) which diminished with increasing lesion baseline severity. The extent of rehardening as a result of the 0 ppm F treatment increased with increasing lesion baseline severity, whereas it decreased for the fluoride treatments. In conclusion, lesion baseline severity impacts the extent of the fluoride dose-response.


Author(s):  
Shulin Wen ◽  
Jingwei Feng ◽  
A. Krajewski ◽  
A. Ravaglioli

Hydroxyapatite bioceramics has attracted many material scientists as it is the main constituent of the bone and the teeth in human body. The synthesis of the bioceramics has been performed for years. Nowadays, the synthetic work is not only focused on the hydroapatite but also on the fluorapatite and chlorapatite bioceramics since later materials have also biological compatibility with human tissues; and they may also be very promising for clinic purpose. However, in comparison of the synthetic bioceramics with natural one on microstructure, a great differences were observed according to our previous results. We have investigated these differences further in this work since they are very important to appraise the synthetic bioceramics for their clinic application.The synthetic hydroxyapatite and chlorapatite were prepared according to A. Krajewski and A. Ravaglioli and their recent work. The briquettes from different hydroxyapatite or chlorapatite powders were fired in a laboratory furnace at the temperature of 900-1300°C. The samples of human enamel selected for the comparison with synthetic bioceramics were from Chinese adult teeth.


Author(s):  
Norman L. Dockum ◽  
John G. Dockum

Ultrastructural characteristics of fractured human enamel and acid-etched enamel were compared using acetate replicas shadowed with platinum and palladium. Shadowed replications of acid-etched surfaces were also obtained by the same method.Enamel from human teeth has a rod structure within which there are crystals of hydroxyapatite contained within a structureless organic matrix composed of keratin. The rods which run at right angles from the dentino-enamel junction are considered to run in a straight line perpendicular to the perimeter of the enamel, however, in many areas these enamel rods overlap, interlacing and intertwining with one another.


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